Most computer and word processor manufacturers utilize standardized keys in their keyboards. One of the most popular standards is that identified as "DIN specifications". DIN is an acronym for Deutsche Industrie Normen, or German Industry Standard.
DIN keys all generally have the same size bases and the same size top surfaces, but the keys vary as to their sculpture depending upon their intended location on the keyboard. In particular, the angle of the top surface with respect to the base varies considerably for key caps in different rows of the keyboard. This variety of sculptures for the key caps presents special problems when one seeks to automate the installation of the key caps on their respective switches.
It has long been recognized that automated movable holders can be utilized to pick up small objects, transport them to an installation site and install the objects on or into associated components. And the use of flexible suction cups to hold and lift the objects is quite common. See for example, the automated egg handling apparatus disclosed in U.S. Pat. No. 2,766,879 granted Oct. 16, 1956, to R. E. Draper for "Egg Handling Apparatus". U.S. Pat. No. 4,007,942 granted Feb. 15, 1977, to H. Hoflinger for "Device For the Uptake of Cup-Shaped Parts of Gelatin Capsules" discloses an automated capsule handling device which employs holders which have vacuum cavities shaped to receive the capsules.
So, the obvious solution to the handling of DIN specification key caps would be to utilize a holder which is specifically shaped to receive each style of cap. Unfortunately, that greatly adds to the cost of the equipment needed to automate the assembly of the key caps because the holder for the caps in one row differs from the holder for caps in the other rows of the keyboard.